How to speed up connection and database discovery.

[AlessandroADG]

Hi,

we are developing a system based on device with nRF52840 S140 ( central and pheripheral).

We developed on both side a custom service.

System is working fine bonding with PM manager.

PM manager is working as I can see that exchange of passekey occurs only at the first connection.

Problem: as we have 4 pheripheral the connection is very slow (several seconds).

Question 1:

Reading documentation about PM it seems possible to store information about service and characteristics. 
I am not sure this information are actually stored. I am sure the information are not used as the system always repeat the database discovery?
Is it possible to cache the information at the first connection to use them in the following connections?
If yes how is it possible to do this? Any example or documentation related?

Question 2:

We know which services and characteristic will be found as we have full control of the pheripheral and we know they will never change.
Is it possible to skip service discovery passing to the SD the needed information?

Thanks

Alessandro

[Simonr]

Hi

Indeed, the peer manager supports storing the remote database on the central side. Typically, it's used so that the database is stored once service discovery is completed when handling the NRF_BLE_GATTS_C_EVT_DISCOVERY_COMPLETE event by calling pm_peer_data_remote_db_store(). 

So when connecting to an already bonded peer at a later point the database is restored by a call to pm_peer_data_remote_db_load(). The GATT service client example does this already for example.

Best regards,

Simon

[AlessandroADG]

Hi,

I will try to implement it.
Only one question looking to the code.

The example is referred to a single link.

I am on a central multilink. 

Do you think pm_peer_data_remote_db_store() and pm_peer_data_remote_db_load() work only with peer database array?

Alessandro